[UDF] executing a javascript function with a syntax error in it returns esoteric error

create this syntactically incorrect javascript function

[root@localhost logs]# curl -X POST http://localhost:43381/api/v1/functions -H 'content-type: application/json' -d '{"name":"math","code":"function add(a, b)

{ let data = a + b return data }

"}'

Now create a n1ql function based on that one:
CREATE FUNCTION javaScriptAdd() LANGUAGE JAVASCRIPT AS

{ "math", "add" }

Run this function:
select javaScriptAdd(6,1)

You get this error:
[

{ "code": 5010, "msg": "Error evaluating projection. - cause: Error executing function javaScriptAdd (math:add): rpc error: code = Unavailable desc = all SubConns are in TransientFailure, latest connection error: connection error: desc = \"transport: Error while dialing dial tcp 127.0.0.1:45173: connect: connection refused\" - cause: rpc error: code = Unavailable desc = all SubConns are in TransientFailure, latest connection error: connection error: desc = \"transport: Error while dialing dial tcp 127.0.0.1:45173: connect: connection refused\"" }

]

sometimes it returns this as well:
[

{ "code": 5010, "msg": "Error evaluating projection. - cause: Error executing function javaScriptAdd (math:add): rpc error: code = Unavailable desc = transport is closing - cause: rpc error: code = Unavailable desc = transport is closing" }

]

It is hard to tell what these errors are for, almost certainly i wouldn't know this is because of a syntax error in my initial javascript